Hi, i saw some mamba bucket seats when i went to a kit car show recently and they seemed like a bit of a "cheap version" of say cobra or sparco etc. they just seemed a bit tatty like the stitching didnt seem perfectly straight, and the padding seemed a little flimsy compared to similar models of the other brands. but that seat in particular does indeed seem to be real carbon fibre and it looks very thin so it should be light if nothing else.
ideally you should try and get to a motor modding shop like motorworld or somethin you might be lucky and find the same seat there.
dont fall for the RRP because that is the RRP of a sparco carbon fibre seat which will be FIA certified i imagine and probably of higher quality.
click on the link to his shop, you can buy them bucket seats all year round so i wouldnt rush and buy one without trying one out first.